ta có: T²-X²=12%

⇒(T-X)(T+X)=12%

mà T+X=50%

⇔T-X=12%/50%=6/25

xét:\(\left\{{}\begin{matrix}T-X=\dfrac{6}{25}=24\%\\T+X=50\%=\dfrac{1}{2}\end{matrix}\right.\\ \Leftrightarrow\left\{{}\begin{matrix}T=37\%\\X=13\%\end{matrix}\right.\)

mà A=T=37%

      G=X=13%

\(\left(x+2y-3\right)^2-4\left(x+2y-3\right)+4\\ =\left(x+2y-3\right)^2-2.2.\left(x+2y-3\right)+2^2\\ =\left(x+2y-3-2\right)^2\\ =\left(x+2y-5\right)^2\)